Cleaning block when replacing head

W

walls

Senior Member
Besides brake cleaner and a rag, is there a best way to clean the block?
is there any spinning disk (scotchbrite or nylon) that would take grime off but be safe for the block?
Previously I’ve used a razor knife and took my time.
Just wondering if there’s any tricks I might not know about.
Merry Christmas
 
Be very cautious when using the spinning abrasive discs. I have seen damage done to bearings and surfaces from some of the residue that got introduced into the inside of the engine. I am not sure if you are talking about just the head mating surface of the whole block. If just the top of the block I used a good scraper and each cylinder stuffed with rags.
 
Roloc bristle disc is safe.. it’s a good idea to run a frayed speedo cable in a drill motor to clean the water jacket, protect the cylinders and valves from debris
 
I used green and white Roloc bristles on my deck and it turned out great. Crank the pistons all halfway down and stuff the cylinders with rags.
 
For paint pre-prep, start first with slow evaporating mineral spirits to attempt to lift 90 years of engine oil from porous cast iron. The mineral spirits with white paper towels until they are 'clean'. Follow this with a quick wipe with naphtha & white towels. Both are flammable, best done with lots of ventilation.

I'm suspicious of lacquer thinner & brake cleaner possibly leaving a film behind to interfere with the paint to cast iron bond.

In doubt, clean it again. Easier than scraping & re-painting.
 
I agree with jb-ob's suggestion to use mineral spirits (paint thinner) along with brushes and rags to remove all the grime. Some areas will need multiple applications. As a final step before painting I use a cloth saturated with alcohol to remove any residual paint thinner.
 
You can use lacquer thinner. It will not leave a residue.

If using mineral spirits, you definitely should use something like lacquer thinner, alcohol or acetone to remove the residue left by the mineral spirits.

Personally, I like lacquer thinner. It does not evaporate quite as fast as acetone.

My experience,

Chris W.
 
Walls,
The more effective cleaners have a toxic nature read the labels. Invest in protective wear for your hands and eyes.
Home Depot stocks an industrial purple de greaser by ZEP that will work thru heavy grease with scrubbing. Other brand names such as purple power are similar. I also use the purple ZEP in my parts soak tank, it will dissolve grease and paint over time. They also have a citrus degreaser by ZEP that is not as toxic but still works ok for lighter de greasing.
I have an assortment of expendable brushes, the better ones are shaped like over sized tooth brushes that get into corners well. Scotch Brite pads work well on flat surfaces.
A good scraper can be made from an old file, shorten to suit your need & grind a 45 deg angle on the end. An old wood handle makes a nice hand hold. Or an old wood chisel.
If re painting after cleaning I will rinse / scrub / rinse with acetone.
 
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After using the solvents mentioned above, I use Dupont 5717S Metal Prep which us a mild acid to etch the surface for best painting surface. This stuff is wiped on (I use coarse steel wool and scrub), keeping the surface wet for 10 minutes. Then rinse with hot water if available and using a clean rag, wipe off and dry. Place parts in the sun if possible to dry fast. Paint as soon as possible. I have engines prepared this way 8 years ago and they still look great.

I might add that a use Metal Prep on most of my steel and cast iron parts for a good painting surface. Ed
 
A bit to the side of this thread, but whenever possible I immerse cast iron (e.g., manifolds, carb bodies, water pump housings, goosenecks) or steel parts in a rust converter (I use Evaporust, but there are others) for 24 hours prior to final cleanup. My order is:

1. Degrease the part, I use primarily Purple Power, then hot water rinse and dry. Repeat with scrubbing as necessary. Sometimes oven cleaner or mineral spirits to get the really tough gunk off.

2. Some parts get an external run through the bead blaster, then hot water rinse to get the beads off.

3. Mineral spirits

4. Brake cleaner

5. Rust converter

6. Hot water rinse and scrub with a toothbrush or similar to get the sulfide residue from the rust converter. Dry immediately to minimize flash rust.

7. Paint as soon as possible

For a block or head (or other large parts) I typically start with a good scrape, then oven cleaner and a high pressure rinse, then mineral spirits, brake cleaner and paint.


JayJay
 
Besides the gasket surface this a good time to be sure the water jackets in the block are clear and open. You can use compressed air and probe with a gas welding rod or coat hanger wire. Tape over the pistons and valves when using compressed air, water jacket crap makes a mess. :)
 
Just re read your question.
Are you interested in cleaning the deck or exterior of the block?
If you are interested in cleaning the deck you are on the right track. I would add to fit a heavy paper towel I inside the cylinder and use a vacuum to remove debris. Solvents can flush junk into the top ring. Wiping down w/solvent is acceptable, apply a little oil to the top ring if you do.
I have a couple of sharp wood chisels dedicated to this cause. The sturdy tool imo is easier than a razor scraper.
 
I think I got lost I read the question as how to clean the block surface when changing the head gasket??? I have used MEK to clean the block surface and a lot of patience.
 
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